High speed photographic objective with large field of view



A. W.- TRONNIER Feb. 2, 1960 HIGH SPEED PHOTOGRAPHIC OBJECTIVE WITH LARGE FIELD 0F VIEW mea April '17. 195s 2 AHR u. b M hwy/322% wk@ |R.\ \\W\w\ NW\ MK3/M. my@ m 5% v2 wm F L Lm mb B m m M m ,m mwm NTOR nnier r INVE Albrecht Wilhelm Tro im MMBY Zim ATTORNEYS United States Patent O HIGH SPEED PHOTOGRAPHIC OBJECTIVE WITH LARGE FIELD F VIEW Albrecht Wilhelm Tronnier, New York, N.Y., asslgnor to Farrand Optical Co., Inc., New York, N.Y., n corporation of New York Application April 17, 1958, Serial No. 729,144 Claim. (Cl. 88-57) 'I'he present invention relates to high speed photographic objectives whose relative aperture lies between 1:1.7 and 1:2.4 and whose useful total field angle amounts to some 56 to 66 degrees.

Attempts have already been made to produce photographic objectives possessing both high speed and wide field. Hitherto however it was in such attempts however necessary to accept a curved image surface, or else it was sought to achieve a satisfactory field flattening by the provision of one or more supplementary divergent eld lenses in the vicinity of the image plane. Such arrangements of field lenses are however afflicted with substantial disadvantages inasmuch as they not only increase the number of lens elements of the objective but also introduce constructional diiculties, for example in the centering of the various elements. In many cases these constructional defects prove in practive insurmountable and have rendered such objectives unusable.

High performance objectives of the type above described but without supplementary field lenses have not hitherto been commercially available. The invention however provides such, and accordingly provides a substantial improvement to the practical photographic art.

The invention effects solution of the problem of pro'-.

viding lenses as above described, with a satisfactorily at eld, by a new disposition of the lens elements. On the long conjugate side the lens of the invention possesses a front assembly presenting its most strongly divergent co'ncave surface to the diaphragm space. 0n the short conjugate side, between the diaphragm and the image plane, the lens of the invention possesses an assembly of Gaussian type including two or more elements.

The invention will be further described with reference to the accompanying drawings in which Figs. 1 and 2 are axial sections through two embodiments of the lens of the invention.

The lens of the inventio'n comprises six components, identified in each of Figs. l and 2 by means of the reference characters I to VI, beginning at the long conjugate side of the lens. The radii of curvature of the front surfaces of the elements (Le. the surfaces presented to the long conjugate side of the system) are identified by the letter R with Arabic subscripts corresponding to the Roman identification of those elements above discussed, and the radii of curvature of the rear surfaces of the elements are identified by the symbol R with similar subscripts. The axial thickness of the elements are identified by the letter d with subscripts which identify the elements in the same fashion, and the axial spacings of the elements are identified by the letter s with double subscripts identifying the elements preceding and follow- 2,923,203 Patented Feb. 2, 1960 ing such spacings. The diaphragm position is indicated by division of the spacing s4', in which it is located into portions b1 and b, preceding and following the diaphragm. The equivalent focal length of the lens is denoted f, and the spacing of the front surface of the rst element L; from the diaphragm position is denoted A. Components I, II, III and VI include one lens element each, identified in the drawings as LI, Ln, Lm and LVI respectively. Components IV and V each comprise, in the embodiments illustrated, two lens elements, those of component IV bearing reference characters Lw. and Lm, while those of component V bear reference characters Lv, and Lvb. i

Components I to IV make up the front assembly -preceding the diaphragm, which is shown at B and components V and VI make up the rear assembly, disposed behind the diaphragm.

The first component I is of negative power and of unequal surface curvatures, and is preferably of meniscus shape. It is disposed at a distance A fro'm the diaphragm B of from 0.7 to 1.4 times the equivalent focal length f. Component I is disposed with its concave surface R', concave toward the diaphragm. The vertex of this surface is spaced from the second component II at a distance sm of from 1A to the equivalent fo'cal length f. Component II is one of three other components II, III, IV all preceding the diaphragm position. Of these three the components II and III are convergent and of these at least one is of meniscus shape. The strongly co'nvergent front surfaces of components II and III are concave toward the diaphragm. The negative meniscus component IV, preferably of two elements as shown, completes the front assembly, and likewise has its two outer surfaces concavel toward the diaphragm.

According to a further feature of the invention the components I to IV of the front assembly possess respectively surface power sums I td fpm which are related to the equivalent total power I of the objective as follows:

In these inequalities the powers I to pw of the components I to IV are obtained by summing the powers of the exterior surfaces of those components respectively. In the notation to be used herein, the sum of the powers of the two surfaces of an element is indicated by the symbol with a Roman subscript identifying the element to which it belongs while the power of a single surface is designated by the symbol qs with an Arabic subscript identifying the element to which the surface belongs, an unprimed value of referring to a front surface and a primed Avalue of referring to a rear surface. In addition, reference will be made to component powers referring, in the case of the single element components I, II, III and VI to the sums of the surface powers of the elements` which make up those co'mponents respectively and, in the case of the two element components IV and V, to the sums of the powers of their exterior surfaces.

The previously stated relation between the equivalent focal length f and the spacing A from the vertex of the rear surface of component I to the diaphragm position may be stated algebraically Yas follows:

The relation between the spacing sm of components I and II and the equivalent focal length f may likewise be written as follows:

The two convergent components II and III and the negative component IV follow the component I as the remaining components of the front assembly.

The rear assembly components V and VI respectively possess surface power sums .pv and pvt related to the total power I as follows:

The zontal variations in the aperture abberations of the lens of the invention can be favorably influenced in relatively simple fashion by appropriate dimensioning of the adjacent rear surface of component II and front surface of component III. According to the invention, there is given to this pair of surfaces a surface power sum corresponding, in order of magnitude, to the surface power sum of the last, convergent component VI on the image side of the system. This relation is according to the invention xed as follows: f

In this relation 12,23 represents the sum of the power of the rear surface of component II and of the power of the front surface component III, sm identifying the spacing of lens element Ln and Lm. psw therefore refers to the power of the air lens constituted by the air space between elements Ln and Lm. At any surface of radius R the power p is given by the difference between the index of refraction n of the medium preceding the surface and the index of refraction n of the medium following the surface divided by the radius of the curvature of the surface, thus, according to the usual formula (n'n) :R

The invention further provides a particularly tine image formation in the lateral portions of the iield by appropriate distribution of power among the optically strong surfaces of the four components of the front assembly. According to this further feature of the invention, the sum (p3-+953) of the powers of the front surfaces of the convergent components II and III lies between 1.7 and 2.8 times the absolute value of the power of the divergent concave rear surface R'1 of the rst component I. Algebraically:

IIn the foregoing, |1| designates the absolute value of the quantity 4:'1. Further, the sum (2+3|4) of the powers of the front surfaces of components II, III and lV is made to lie between 3.4 and 5.6 times the absolute value of the power ep', of the divergent rear surface of component I, which is concave toward the diaphragm. Algebraically:

Three examples of the lenses of the invention will now be given, with data therefor in tabular form. The general form of the lens of Example 1 is shown in Fig. 1 and that of Examples 2 and 3 in Fig. 2. The glasses employed are identified by their ndices of refraction n for the yellow d line of helium whose wave length l. is 5876 Angstroms, and by their Abbe numbers y. In each of the following examples there is further given the equivalent focal length f and the last intersection distance p'o on the image side of the system, for an infinitely distant object. The useful relative aperture is also given and so is the iield angle 2m, on the object side of the system. The objectives of theseexamples are, in aeeord ance'with the essential properties of the lens of the invention, provided with anastigmatic field flattening and consequently require no supplementary field attening field lenses.

The rst example to be considered is a lens of relative aperture f/2.l, whose total ield angle 2mg is 58. For an equivalent focal length f of mm. and corresponding total power L of 10 diopters, the general distribution of powers in this lens is as follows:

In this lens the distance A from the front surface of component I to the diaphragm position is 0.99 f and the spacing su of components I and II is 0.45f.

While the foregoing table gives the general distribution of powers among the lens components, a more accurately stated distribution which shows the apportionment of the powers of components IV and V among their two elements LW. and Lm, and Lv, and L, is as follows:

TABLE 2 Apportionment of the powers of the eight elements given in the last table between their individual surfaces gives for the lens of Example 1 the following distribution of individual surface powers (again assuming I =10 dptr.):

TABLE 3 l --5.85 dptr.

n +4.63 dptr.

ammi-6.63 dptr.

eww-9.38 dptr.

v --3-90 dptr.

There may be used for the eight elements of the lens of Example 1 commercially available glasses having respectively indices as follows:

TABLE 4 n,=1.56 (low index dense crown) n,=1.56 (medium barium glass) n3=1.67 (dense barium int) n4=l.68 (barium lanthanum crown) n4b=l.65 (normal dense iint) n5a=1.55 (medium phosphate glass) n5h=1.63 (double light flint) n=1.50 (light phosphate crown) -With these glasses and with appropriate lens thicknesses, the data for the lens .of theirst example is as fol- 2,928,208 5 6 The constructions! form of the lens of the invention lows (rewritten for an equivalent focal length f of 1 maybesymboiicaiiy writtenas mm* U+U+Mv diapnnm n4-v TABLE 5 [Lineerdixnendonsinmeml Relative aperture: 2.1 Total iield angle: 2am-58 Equivalent focal length: f-l meter Equivalent total power: le-l diopter Diaphragm position: 0.154 meters from element Ln Component Element Radii Thickness d or Index oi' Re- Spacing a fraction n R -+3.i rn. I............... L. 1 i1-0.05 m. irl-1.58

nhg-0.45 m. n, |i.0 m. IL.-. Ln d|0.07 m. '1n-1.66

Ita-0.01 m. R; +0.56 m. m......-........... Lm diiom. nz-1.67

R; Inl-1.26 m. m +o san-0.01 m.

l m. 'L1'. div-0.15 m. 1in-1.68

Ru-3.6 m. IV mas-0 (cemented) Roi 3.6 m. Live dis-0.02 m. nis-1.65

Rub-+0.25 m.

MPIO 5 In. 11;. --oz m. Lv. dni-0.06 m. l 'nhl-l. 55

Rfk- 0.22 m. V. ai-.iv-O (cemented) Ri., --om m. Lvb du. 0.02 m. 'mb-l1. 53

Rib--OA3 m.

9m-0.01 m. Re 'hi-2.5 m. VI.. Lvl d0.08 m. 'ln-1.50

R', --ou m.

The foregoing Table 5 gives data for the lens of Exin which U represents a component of unequal exterior ample l with third order corrections included. Modisurface curvatures, M a meniscus component and D a cation of this data to the highly corrected state contemdoublet, and in which the plus or minus sign refers to plated and permitted by the invention gives the following 40 the convergent or divergent power of the component. The datal for the lens of that example, according to the innegative meniscns component V of Gaussian type adjavention: cent the diaphragm can be constructed in the usual man- TABLE 6 [Linear dimensions in meters.]

Relative aperture: ,02.1

Total field angle: 2we=58 Equivalent focal length: f-l meter Equivalent total power: i 1 diopter Diaphragm position: 0.15411 meters behind element Lxvi,

Short conjugate side intersection distance for object at infinity: p'=0.7i246 meters Compo- Element Radii Thickness d or Index of Abbe nent Spacing a Refraction n number r R1 +3.1291 m. I L! d1=0.04957 m. n! 1.5596 iq =61.2

R'1 sel-0.7323 m.

a|.g==0.44570 in. Re 'r4-1.0698111. II Ln 1g-0.07511 m. 114 -1.5625 vz 50.9

R', '+9.0l26 m.

81,:*000469 m. Rx lvl-0.5610 m. TTT Lm dp=0.08675 m. m 1.6700 vr *47.2

R: I4-1.2604 m.

IgA-0.00225 m. R4. +0.3981 In. Liv di.=0.l5397 m. m.-1.6779 vil-55.5

RMU-3.6144 m. IV ai.,4s==0 (cemented) Rib -3.6l44 m. Lxvb dib=0.02159 m. nib-1.6490 vib33.8

R'4b=l+0.2450 m.

im-0.28540 m. Rn 0.3200 m. Lv. d..o.ose1s m. 11h-1.5523 ...-63.5

Rigi-0.2199 m. v .mas-0 (cemented) Rn, -0.2199 m. Lvb dsb0.01690 D1. 1155815317 rgb-48.9

IVW- 0.4281 m.

sin-0.00967 in. vr L R' H5442 m' di 007511 i 503s se 7 vx in. m n

ner as a divergent doublet whose negative element is adjacent the diaphragm, as shown in Fig. 1. Alternatively as shown in Fig. 2, this doublet can be arranged with its convergent element adjacent the diaphragm and with its negative element remote from the diaphragm, enclosed by two positive elements. This latter arrangement makes possible for the rst time the use of glasses of low index even in wide angle objectives of high speed, the use of such glasses having been hitherto limited either to wide angle lenses of low speed or to high speed lenses of narrow lield angle. Consistently with the invention moreover the performance of the lens described may be increased by the use of high instead of low index glasses, for either greater speed or improved correction or wider ield.

Example v2 TABLE 7 [Linear dimensions in millimeters.)

Relative aperture: 172.0

Total tleld angle: 2u=61 Equivalent local length: 100 mm. Equivalent total power: @=10.0 diopters Image side intersection distance for infinite Diaphragm position: 15.6400 mm. behind Lr Example 3 In the Example 3 now to be given the components Il and VI, which are the convergent components in the front and rear assemblies respectively farthest from the diaphragm, are provided with larger axial thicknesses, and this example shows a slight reduction of various surface powers. By these means the useable diameters of components II and VI can be made especially large so that even large cross-sections for the comatic bundles are enabled to pass through the objective with only slight vignetting. For purposes of comparison the choice of glasses used in Example 2 has been retained, and so has the relative aperture of the objective and its iield angle.

With these points of departure the general distribution object: po=71.2426 mm.

Com- Element Radii Thickness d or Index oi re- Abbo numponent Spacing e fraction n ber v R1 =+314.2o4 mm. I Li al1-4.9840 mm. n, =1. 56011 l 61.oo

R', +73.47i6 mm.

slm-44.7510 mm. R9 =+107.505 mm. II Lu d,=7.9429 mm. m 1.56296 n =50.90

Rz =+911.589 mm.

sem-0.2367 mm. R: ==+56.3365 mm. III Lm d1=8.9423 mm. n3 ==l.67050 v: =47. 59

R'a +126.560 mm.

ss.=0.1315 mm. Ri. =+39.9774 mm. Liv. d4.=14.9126 mm. m.=1. 67811 w.==55. 58

R'i 364.005 mm. IV inab Rab =365.005 mm. Livb db=2564 mm. mb=1. 04838 v4b=33.8

R'4b=+24.5256 mm.

84,52%.6548 mm. R5. =32.1529 mm. Lv d=5.9440 mm. mp1. 55262 vsp-63. 30

RHP-21.9218 mm. v lbo Ris =21.9218 mm. Lvb dim-1.6964 mm. niv-1. 53232 rsb=48.90

- R'ib=42.9625 mm.

sim-0.2236 mm. Ra 1i-259.458 mm. VI Lvl d9.0344 mm. m =1. 50476 vi =65.94

Re l#-67.8563 mm.

The lens of Example 2 possesses the following surface, element and component powers:

of powers in the lens of Example 3 has the following form (assuming a system equivalent power I of 10 diopters:

To this distribution of powers among the individual lens components there corresponds the following data for the lens of Example 3:

TABLE 10 [Equivalent focal length f-100 mm.)

Thickness d or Index of Abbo Component Element Radii Spacing a refraction number R +34 L-.. L! l lil-0.05f m 1. 65 v1 61 R', +o.75f

lm-0.45 f Re +1.09 f II Ln tin-0.09)' m 1. 58 vn 51 Rz --HOA .1m-0.0021' Rl +o-5431'V mn.. Lm d| 0.09f m 1. 67 vl 48 R'a +1.26f R. +0 40! #3.0-0.001f

o Llv. tin-0.15 f m.- 1. 68 rel-56 Elli- 3.6 f IV... t mb-0 Reb -3.6 f Lxvb dfb-0.03 f nib-r1. 65 vih-34 R'4b+024f #HHG-29] Rl. -0.32f Lv. d1. 0.06f m.=1. 55 vsn-63 R'|. 0.22f V.... 8||.|b=0

Rib --0.22] Lvl, d|b=0.02f nib-1. 53 nb 49 Rn, 0.43f

' 8|.s=0.002 f Rg +2.6f VL Lvl d=0.1 f m 1. 50 n 67 Diaphragm position: 0.16 f behind Live.

Upon introduction of ne corrections into the approximate data of the preceding Table 10 and with change of values to correspond with a focal length f of 100 mm.,

the lens data assumes the following form (dimensions in In the systems whose data are given in Table 11, the intersection distance on the image side amounts, for an infinitely distant objective, to p'0=70.9884 mm.

The individual surface powers and the element and mm.): 40 component powers of the lens Systems whose data are TABLE 11 Compo- Elexnent Radil Thickness d or Index oi Abbo nent Spacing a refraction 'n number v R1 +33'I.175 mm. I.......- L1 i1-4.9751 mm. 'n1-1.56017 :f1-61.00

RQ -+74.5996 mm.

81.1 445705 mm. R1 +108.979 mm. II Ln d;=9.2413 mm. m==l. 56296 1 50. 90

, RI ==+104L82 mm.

exa-0.2363 mm. Re =+56.2352 mm. III Lm ds=8.9262 mm. m=1.67050 vai-47.59

' R'a +126.332 mm.

8|.4=0.1313 mm. R4. =+39.9055 mm. Liv. 4.1445858 mm 71h81. 67811 n.155. 58

R4.- -363.350 mm. IV '4me-0 R45 =363.350 mm. Lxvb dfb-2.6516 mm. mb=1.64838 lub-33.86

R'4b=+24.4815 min.

a4.i=28.6333 mm. Rg. =32.0950 mm. Lv. iw-5.9333 mm. m|=1. 55262 vgl-63. 30

Rsnl 21.8824 mm. V.. n.abf

Rab =21.B824 mm. Lvb 5511.6934 mm. llxb=1.53232 51,248.90

Rn, 42.8853 mm.

` ami-0.2232 mm. R; +258.992 mm. VI Lvl lil-9.8845 mm. 'ns-1. 50476 n 6.94

R. =67.7343 mm.

given in Table l1 are given as multiples of the equivalent system power I in the following Table 12.

I claim:

1. A high speed objective lens system comprising, from front to back and in front of the di hra position, a first negative component, said negative componen Having unequal surface curvatures and having its strongly divergent rear surface concave toward the rear, first and second positive components of which at least one is of meniscus shape and of which both have their convergent front surfaces concave toward the rear, and a second negative component, said second negative component being of meniscus shape and having both of its exterior surfaces concave toward the rear, and, behind thediaphragm position, a rear assembly of Gaussian type, said first negative component being spaced from the diaphragm position by from 0.7 to 1.4 times the equivalent focal length of the objective system, the spacing of said first negative and first positive components lying between one-third and two-thirds of said fol length, and the most strongly divergent surface of said front assembly being adjacent the diaphragm position.

2. An objective lens system according to claim 1 in which said second negative component comprises at least two elements.

3. An objective lens system according to claim 1 in which the sums p1 to prv of the powers of the exterior surfaces of the four components I to IV in front of the diaphragm position, numbered from front to back, are related to the equivalent power 1 of the system as follows:

4. An objective lens system according to claim 3 in which the sum psu of the powers of the rear surface of the first positive component II and of the front surface of the second positive component III is related to the equivalent power KI of the system as follows:

5. An objective lens system according to claim 3 in which the sum (m4-953) of the powers of the front surfaces of said first and second positive components II and III is related to the absolute value of the power pl of the rear surface of said first negative component I as follows:

i 12 6. An objective lens system according to claim 5 ir which the sum (3|3+4) of the powers of the front surfaces of the first and second positive components II and III and of the second negative component IV is related to the absolute value of the power of the rear surf'ace of the first negative component I as follows:

7. An objective lens system according to claim 3 in which the sums I to pvt of the powers of the exterior surfaces of the six components I to VI respectively are related to the equivalent power d of the system substantially as follows:

8. An objective lens system according to claim 3 in which the sums I to :pw of the powers of the exterior surfaces of the six components I to VI thereof respectively are related to the equivalent power I of the system substantially as follows:

and in which the sums olv., m, va, and vb of the front and rear elements of components IV and V respectively are related to the equivalent power I of the system substantially as follows:

9. A high speed objective lens system comprising, from front to back, a negative element LI, first and second positive elements Lu and Lm, a positive element Lm, and a negative element Lwb, and, behind the diaphragm position, elements Lva, Lvl, and LVI, said objective lens having anequivalent focal length f, said elements conforming substantially to the following conditions:

10. A high speed objective lens system comprising, from front to back, a negative element LI, rst and second positive elements Ln and Lm, a positive element LW, and a negative element Lm and, behind the diaphragm position elements Lvl, LV1, and Lv; said objective lens having an equivalent focal length f, said elements conforming substantially to the following condi- Element Radii Thickness d or Index of Re- Abbe num- Spacing s fraction n ber v R1 -|3.1291 m. L1 d1==0.04957 m. 'my 1=1. 5596 n 61. 2

Rg =+0.7323 m.

8|.a=0.44570 m. Rg hl-1.0698 m. Ln d|=0.07511 m. m l 1. 5625 n *50. 9

R's |9.012 m.

h.x=0.00469 m. R1 -|0,5610 n1. Lm eil-0.08675 m. m u1. 6700 n 47. 2

Rg 44.2604 m.

.tm-0.00225 m. R4. 'I4-0.3981 m. Ln. dnl-0.15397 m. nil-1. 6779 ris-55. 5

Will-3.6144 m.

mAb-0 (cemented) Rn, 3.6144 m. I4 dus-0.02159 m. ms-l. 6490 nhl-33. l R's-+0.2450 m. v

lig-0.28540 m. Rg.- 0.3200 m. Lv. 1h-0.05916 m. flu-'1. 5523 ln-63. 5

Rs.- 0.2199 m.

m4n-0 (cemented) Rnb 0.2190 m. Ln. duh-0.01690 m. mb- 1. 5317 lb-48. 0

RGB- 0.4281 m.

nal-0.00967 m. Rg +2.5442 m. Lu 1g-0.07511 m. In 1. 5038 n .66.7

Menaces Cited in the le of this patent UNITED STATES PATENTS FOREIGN Pimm-ls France May 4, 1955 UNITED STATES PATNT OFFICE CERTIFICATE oF CORRECTION Patent No. 2,923,203 February 2, 1960 Albrecht Wilhelm Tronnier It is hereby certified that error a of the above numbered patent requiring c Patent should readas corrected below.

ppears in the printed specification orrection and that the said Letters Column 4, line 7l, Table 4, for "1.63" rea@ 1.53 column 5, Table 6, sixth column thereof, third item, for ")2=47.2" read -)3=47,2

Signed and sealed this 26th day of July 1960.,

(SEAL) Attest:

KARL H. AXLINE ROBERT c. WATSON Attesting Oicer Commissioner of Patents 

